| 1 | /* |
| 2 | ** $Id: lmem.c,v 1.84 2012/05/23 15:41:53 roberto Exp $ |
| 3 | ** Interface to Memory Manager |
| 4 | ** See Copyright Notice in lua.h |
| 5 | */ |
| 6 | |
| 7 | |
| 8 | #include <stddef.h> |
| 9 | |
| 10 | #define lmem_c |
| 11 | #define LUA_CORE |
| 12 | |
| 13 | #include "lua.h" |
| 14 | |
| 15 | #include "ldebug.h" |
| 16 | #include "ldo.h" |
| 17 | #include "lgc.h" |
| 18 | #include "lmem.h" |
| 19 | #include "lobject.h" |
| 20 | #include "lstate.h" |
| 21 | |
| 22 | |
| 23 | |
| 24 | /* |
| 25 | ** About the realloc function: |
| 26 | ** void * frealloc (void *ud, void *ptr, size_t osize, size_t nsize); |
| 27 | ** (`osize' is the old size, `nsize' is the new size) |
| 28 | ** |
| 29 | ** * frealloc(ud, NULL, x, s) creates a new block of size `s' (no |
| 30 | ** matter 'x'). |
| 31 | ** |
| 32 | ** * frealloc(ud, p, x, 0) frees the block `p' |
| 33 | ** (in this specific case, frealloc must return NULL); |
| 34 | ** particularly, frealloc(ud, NULL, 0, 0) does nothing |
| 35 | ** (which is equivalent to free(NULL) in ANSI C) |
| 36 | ** |
| 37 | ** frealloc returns NULL if it cannot create or reallocate the area |
| 38 | ** (any reallocation to an equal or smaller size cannot fail!) |
| 39 | */ |
| 40 | |
| 41 | |
| 42 | |
| 43 | #define MINSIZEARRAY 4 |
| 44 | |
| 45 | |
| 46 | void *luaM_growaux_ (lua_State *L, void *block, int *size, size_t size_elems, |
| 47 | int limit, const char *what) { |
| 48 | void *newblock; |
| 49 | int newsize; |
| 50 | if (*size >= limit/2) { /* cannot double it? */ |
| 51 | if (*size >= limit) /* cannot grow even a little? */ |
| 52 | luaG_runerror(L, "too many %s (limit is %d)", what, limit); |
| 53 | newsize = limit; /* still have at least one free place */ |
| 54 | } |
| 55 | else { |
| 56 | newsize = (*size)*2; |
| 57 | if (newsize < MINSIZEARRAY) |
| 58 | newsize = MINSIZEARRAY; /* minimum size */ |
| 59 | } |
| 60 | newblock = luaM_reallocv(L, block, *size, newsize, size_elems); |
| 61 | *size = newsize; /* update only when everything else is OK */ |
| 62 | return newblock; |
| 63 | } |
| 64 | |
| 65 | |
| 66 | l_noret luaM_toobig (lua_State *L) { |
| 67 | luaG_runerror(L, "memory allocation error: block too big"); |
| 68 | } |
| 69 | |
| 70 | |
| 71 | |
| 72 | /* |
| 73 | ** generic allocation routine. |
| 74 | */ |
| 75 | void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) { |
| 76 | void *newblock; |
| 77 | global_State *g = G(L); |
| 78 | size_t realosize = (block) ? osize : 0; |
| 79 | lua_assert((realosize == 0) == (block == NULL)); |
| 80 | #if defined(HARDMEMTESTS) |
| 81 | if (nsize > realosize && g->gcrunning) |
| 82 | luaC_fullgc(L, 1); /* force a GC whenever possible */ |
| 83 | #endif |
| 84 | newblock = (*g->frealloc)(g->ud, block, osize, nsize); |
| 85 | if (newblock == NULL && nsize > 0) { |
| 86 | api_check(L, nsize > realosize, |
| 87 | "realloc cannot fail when shrinking a block"); |
| 88 | if (g->gcrunning) { |
| 89 | luaC_fullgc(L, 1); /* try to free some memory... */ |
| 90 | newblock = (*g->frealloc)(g->ud, block, osize, nsize); /* try again */ |
| 91 | } |
| 92 | if (newblock == NULL) |
| 93 | luaD_throw(L, LUA_ERRMEM); |
| 94 | } |
| 95 | lua_assert((nsize == 0) == (newblock == NULL)); |
| 96 | g->GCdebt = (g->GCdebt + nsize) - realosize; |
| 97 | return newblock; |
| 98 | } |
| 99 | |